Hinged attachment of headgear to a helmet

ABSTRACT

A hinge mechanism for attaching ear accessories to a helmet allows an accessory to be attached at a point outside the helmet shell utilizing, for example, a slidable mounting rail, and to reach under the edge of the helmet shell so that the accessory is supported in contact with the wearer&#39;s head. The hinge mechanism is well suited for use in connection with military helmets that have a “bulge” or protrusion over the ear.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Ser. No. 13/224,559,filed on Sep. 2, 2011, which is continuation of U.S. Ser. No.11/760,412, filed on Jun. 8, 2007, now U.S. Pat. No. 8,028,344, which isa continuation-in-part of U.S. Ser. No. 11/350,591, filed on Feb. 9,2006, now U.S. Pat. No. 7,908,667, which claims priority to, and thebenefits of, U.S. Ser. No. 60/691,307, filed Jun. 17, 2005, U.S. Ser.No. 11/760,412 also claims priority to U.S. Ser. No. 60/811,896, filedon Jun. 8, 2006. The entire disclosures of these applications are herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to safety helmets, and in particular toattachment of accessories that may be optionally mounted onto thehelmet.

BACKGROUND OF THE INVENTION

Helmets for head protection are worn in a variety of environments andfor various purposes. Accessories may be added to the helmet accordingto the needs of the wearer and the demands of the use environment. Suchaccessories may, for example, provide additional protection, as in thecase of a face shield; additional capability such as night vision; orcommunication in the case of earpieces.

Ear accessories (e.g., communications devices integrated within a paddedearphone) can be critical in numerous helmet deployments; for example,the need for both protection and communication is particularly importantin military, fire-fighter, rescue and similar activities. The prior artincludes two approaches: ear accessories built into the helmet, and earaccessories worn separately beneath the helmet. An example of a helmetwith built-in earphones is the present military helmet known as theCombat Vehicle Crew (CVC) helmet. Unfortunately, because the earphonesadd weight and do not function in dismounted operations, and cannot beremoved, the vehicle crew members are issued two helmets—the CVC helmetand a standard infantry helmet.

The Modular Integrated Communications Helmet (MICH) supports earphonesworn beneath the helmet. The earphones are donned first and the helmet,in use, rests on the wearer's head atop the earphone headband. Toaccommodate the space required for the earphone headband, the padswithin the MICH helmet are removed or repositioned according to thewearer's head shape and size. In some cases this repositioning resultsin improper fit and/or less protection in the case of impact. Wearersmay also experience discomfort due to the extra layer of retentionelements separately holding the earphones and the helmet.

SUMMARY OF THE INVENTION

The present invention provides a hinge mechanism for attaching earaccessories to a helmet. The hinge mechanism allows an ear accessory tobe attached at a point outside the helmet shell utilizing, for example,a slidable mounting rail, and to reach under the edge of the helmetshell so that the accessory is supported in contact with the wearer'shead. The hinge mechanism of the present invention is well suited foruse in connection with military helmets that have a “bulge” orprotrusion over the ear.

In some embodiments, a pivot arm of the hinge mechanism allows the earaccessory to extend below the edge of the helmet and, alternatively, tofold into a lower-profile configuration for stowage. The pivot arm mayinclude a split ring that facilitates attachment to the posts ofstandard earphones. In particular, by removing a screw and separatingthe split ring into two parts, it may be placed around the posts ofstandard earphones, and secured by reinserting and tightening the screw.By replacing the existing ear-accessory support with the pivot arm ofthe present hinge mechanism, ear accessories that have already beenfielded can be retrofitted in accordance herewith. The pivot armdesirably also provides clearance for any wires exiting the earaccessory and, depending on the application, clearance to access abattery compartment of the accessory.

The overall length of the pivot arm is selected to facilitatepositioning and removal of the ear accessory around the edge of thehelmet shell. The length from center of the pivot point where the pivotarm joins the connecting member and the center of the split ring may be,for example, between 0.5 inch and 2 inches (e.g., 1.25 inches). Thepivot arm may include features that facilitate adjustment of thepressure placed by the ear accessory on the wearer's ear.

In some embodiments, a connecting member is pivotably connected to thepivot arm and slidably joined to a shoulder member, thereby forming anattachment assembly. The pivot arm and connecting member joined togethermay also be optionally attached to a conventional headband (instead ofjoining the shoulder member) to support the ear accessory without thehelmet. The slidable connection between the connecting member andshoulder member provides adjustment of the ear accessory in height toobtain a comfortable position over the wearer's ear.

A shoulder member may support connection of the hinge mechanism to thehelmet, for example, using the slidable mounting rail described below(it being understood that alternative means for attaching the shouldermember to the helmet may be substituted without detracting from thebenefits of the present invention). The shoulder member of the hingemechanism may also provide rotation to allow the ear accessory to rotateto the back of the helmet, facilitating stowage when the accessory isnot needed.

A preferred mounting platform (herein referred to as a “mounting rail”)accepts the ear-accessory hinge mechanism and, if desired, additionalaccessories at desired locations and with positional security. Themounting rail may have slides, threaded holes, or other mountingfixtures suited to securing the accessories. The mounting rail may beconfigured to present a relatively low-profile protrusion from thehelmet using physical surfaces that offer low risk of snagging or beingcaught in external devices when accessories are not in place. Themounting rail allows for adjustment of the position of the accessorieswhen they are attached to the rail, which desirably accepts more thanone optional accessory.

The mounting rail utilizes an interface structure secured to the outershell of the helmet, providing surfaces for mounting accessories ontothe mounting rail instead of directly onto the helmet. In someembodiments, the mounting rail may be secured to the helmet shell usingexisting through-holes in the helmet shell and the fasteners alreadyemployed in connection with helmet-retention components such as strapsor headbands. The fasteners may be, for example, rivets or nuts andbolts and may be made from plastic (for light-duty applications),stainless steel, or forge-hardened steel (for helmets providingballistic protection).

A preferred embodiment of the mounting rail comprises a molded componentconforming to the shape of the outer shell of the helmet. In someversions, the bottom edge of the rail fixture (which itself includes oneor more rails) conforms to the bottom edge of the helmet, while in otherversions, the entire fixture is raised on the side of the helmet,residing, for example, over (and conforming to at least a portion of) abulge or other protrusion or discontinuity in the helmet. The railfixture desirably spans a sufficient circumference of the helmet shellto overlap at least two existing through-holes provided for securingretention components thereto. The mounting rail may then be secured tothe helmet shell by sharing fasteners with the retention componentsusing these through-holes. A benefit of this embodiment is that themounting rail can be added to already-manufactured helmets by providingthe appropriate mounting rail with mounting holes at the dimensions ofthe existing through-holes in the helmet. If necessary, modifiedfasteners, which may be longer than the standard fasteners, can beprovided to secure both the mounting rail and the existing retentioncomponents using the existing through-holes. Avoiding the need foradditional through-holes to secure the mounting rail means that thesafety features of the shell are not altered. It should be stressed,however, that the use of existing through-holes is by no meansnecessary. Other approaches such as co-molding or thermo-bonding withthe shell, bonding using adhesives, or a combination of adhesives andone or more fasteners can be used to secure the mounting rail to thehelmet shell (or to fabricate it integrally therewith).

As used herein, the term “rail” refers to a mounting facility withparallel boundaries, and which slidably accepts a complementaryengagement member. The preferred embodiment of the mounting railincludes a recessed groove open on at least one end and preferably onboth ends. Accessories having an engagement member complementary to therecessed groove may be attached to the mounting rail by sliding theengagement member into the mounting-rail groove and securing it inplace. The preferred cross-sectional profile for the groove is flat onthe surface toward the helmet with angular side walls; thisconfiguration is sometimes referred to as a dove-tail recessed groove.The opening width of the groove may range from 0.25 to 1.0 inch (and ispreferably 0.75 inch) with walls angled inward from 30° to 60° (andpreferably at 45°). The dovetail shape retains the attaching componentby means of the angled walls, but the profile may be any suitablyretentive shape (such as an “L” or “T” shape) having edges that slidablyretain an attaching component, allowing it to reach a desired positionwhere it is secured into place. Means for securing the position of themounting element are well known in the art and may include, for example,a “thumbscrew” tightener or a “tab-and-slot” engagement mechanism.

Accordingly, in a first aspect, the invention relates to a mountingfacility for a safety helmet of the type having a bulge or protrusion ona side thereof to form a cavity therein, where the cavity extends to aterminal edge of the helmet and overlies a wearer's ear. The mountingfacility comprises a fixture configured for attachment to the helmetabove the bulge and, attached to the fixture, an articulating armassembly for receiving an ear accessory. The arm assembly facilitatesinsertion of the ear accessory into the cavity and its removal therefromaround the terminal edge.

In some embodiments, the articulating arm assembly includes a jointmechanism facilitating rotational downward and inward movement of theear accessory relative to the terminal edge. The joint mechanism maycomprise first and second hinges, and the articulating arm assembly maycomprise a flexible member that resists outward movement of the earaccessory relative to the wearer's head, thereby holding the earaccessory in contact with the wearer's head. The articulating armassembly may also comprise means for adjusting a distance between theear accessory and the terminal edge of the helmet. The mounting facilitymay further comprise means facilitating rotation of the articulating armto place the ear accessory behind the helmet and/or means for adjustablylimiting rotation of at least one of the hinges.

In a second aspect, the invention relates to an articulating armassembly for use with a safety helmet of the type that has a bulge orprotrusion on a side thereof to form a cavity therein, where the cavityextends to a terminal edge of the helmet and overlies a wearer's ear.The arm assembly comprises means for engaging an ear accessory and meansfacilitating insertion of the ear accessory into the cavity and itsremoval therefrom over the terminal edge. The articulating arm assemblymay comprise a flexible member that resists outward movement of the earaccessory relative to the wearer's head, thereby holding the earaccessory in contact with the wearer's head, and/or means for adjustinga distance between the ear accessory and the terminal edge of thehelmet.

In a third aspect, the invention relates to a safety helmet comprising abulge or protrusion on a side thereof to form a cavity therein, thecavity extending to a terminal edge of the helmet and overlying awearer's ear, a fixture attached to the helmet above the bulge and,attached to the fixture, an articulating arm assembly for receiving anear accessory. The arm assembly facilitates insertion of the earaccessory into the cavity and its removal therefrom over the terminaledge. The helmet may include other features as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention. In the followingdescription, various embodiments of the present invention are describedwith reference to the following drawings, in which:

FIG. 1a shows the left side of a helmet having a mounting rail;

FIG. 1b shows the left side of a helmet having an alternate mountingrail;

FIG. 2 is a cross-section of the mounting rail shown in FIG. 1b takenalong the section 2-2;

FIG. 3a is a cross-section of the mounting rail shown in FIG. 1b takenalong the section 3-3;

FIG. 3b is a cross-section similar to FIG. 3a showing an alternativeform of the mounting rail of FIG. 1 b;

FIG. 4a shows the mounting rail of FIG. 1b with two accessoriespositioned to be attached;

FIG. 4b shows the mounting rail of FIG. 4a with the two accessoriesmounted in place;

FIG. 5 shows another embodiment of the present invention havingadditional means of attaching accessories to a first mounting rail;

FIG. 6 shows a perspective view of the mounting rail of FIG. 5 with anaccessory mounted to the front;

FIG. 7 is a view from the back of the helmet of FIG. 5 showing anadditional element for containing and/or supporting accessories;

FIG. 8A shows the left side of a helmet incorporating an embodiment ofthe hinged ear-accessory mechanism of the present invention, with anearphone attached to the helmet and positioned over the wearer's earsfor normal use;

FIG. 8B shows the helmet of FIG. 8A with the hinge mechanism andearphone assembly moved downward to an intermediate position;

FIG. 8C shows the hinge mechanism and earphone assembly moved fullydownward and outward prior to removing or stowing the earphone;

FIG. 8D shows the manner in which the earphone may be rotated into thestowage position;

FIG. 9 shows a hinge mechanism in accordance with the present inventionwith an earphone attached;

FIG. 10 illustrates the pivot arm of the hinge mechanism separated fromother parts;

FIG. 11 is an exploded view of the hinge mechanism illustrated in FIG.10;

FIG. 12A shows selected components of a hinge mechanism in order toillustrate the interaction among components;

FIG. 12B shows selected components of a hinge mechanism in order toillustrate interference between components of the hinge mechanism;

FIG. 12C illustrates an alternate embodiment of the adjusting mechanism;

FIG. 13 shows a hinge mechanism assembled with an earphone and attachedto a helmet, illustrating the alternate positioning of the assembly atthe back of the helmet; and

FIG. 14 shows the pivot arm and connecting members of the hingemechanism assembled with an earphone and separated from the helmet,positioned to be assembled with a conventional headband for use withoutthe helmet.

DETAILED DESCRIPTION

For ease of presentation, the present discussion focuses first on asuitable mounting rail to which a hinged ear-accessory retention systemmay be mounted; preferred embodiments of the ear-accessory retentionsystem itself are then described.

Mounting Rail

With reference to FIG. 1a , a helmet shell 51 is shown from the leftside of the user's head (the right side having symmetrical features). Amounting rail 55 is included within a fixture preferably fabricated fromnylon, polypropylene, or other synthetic plastic using injection moldingprocesses, the bottom edge of which conforms to the bottom edge of thehelmet shell 51. The fixture is secured to the exterior of helmet shell51 by means of fasteners 53 in the front and back. In anotherembodiment, illustrated in FIG. 1b , mounting rail 55 is included withina fixture having a bottom edge that conforms to a convex extension 56 ofhelmet shell 51.

A recessed groove 57 in the mounting rail 55 slidably accepts acomplementary engagement member 59 of a potential accessory, which maybe secured by tightening a securing member 60 (e.g., a standard screw,as illustrated, or a thumbscrew, tab-and-slot system, or other suitableengagement mechanism). The engagement member 59 shown in FIGS. 1a and 1bis illustrative only; in practice, it would carry a functionalaccessory. Virtually any accessory suitable for mounting to the helmet51 can be designed to have an engagement member complementary to therecessed groove 57.

In FIG. 2 the mounting rail 55 is shown in cross-section, mounted onhelmet shell 51. In the illustrated embodiment, the cross-sectionalprofile of the recessed groove 57 is a dove-tail configurationcomplementary in cross-section to that of an attaching component 59. Thedovetail shape retains the attaching component 59 by means of the anglededges 61, but allows it to slide within the recessed groove 57 to reacha desired position where it is further secured by a tightening screw 64.The ends of the mounting rail 55 desirably slope toward the surface ofthe helmet shell 51.

As shown in FIG. 3a , the mounting rail 55 provides a geometricalinterface between the curving surface of the helmet shell 51 and astraight groove 57. A straight groove 57 is beneficial because it allowsattaching component 59 to be formed with simple flat surfaces whilestill allowing adjustment of the position of the accessory along thelength of the groove 57.

On the other hand, as shown in FIG. 3b , another embodiment of themounting rail utilizes a non-straight recessed groove 67. The innersurface of the mounting rail 65 has a contour that conforms to thehelmet shell 51, and the recessed groove 67 also approximates the curvedsurface of the helmet shell 51 but with a constant radius. The curvedgroove 67 has the benefit of reducing the protrusion at the ends of themounting rail 55 shown in FIG. 3a . If the recessed groove 67 has aconstant radius, the attaching component 59 can have a matching curvedshape and still freely slide within the groove 67. The mounting rail 65provides an interface between differently sized helmets having differentamounts of curvature and a groove 67 with a common constant radius(independent of the size and curvature of the helmet). For accessoriesthat do not require the flat surface as shown in FIG. 3a , and thus thelower profile of mounting rail 65 shown in FIG. 3b , a curved mountingrail may be preferred.

FIG. 4a shows the mounting rail of FIG. 1 mounted on helmet shell 51with two accessories 75 and 80 positioned to be attached. The earphoneaccessory 75 is described below; a similar earphone can be mounted onthe right side of the helmet in a symmetrical mounting rail (not shown).As described below in connection with FIG. 8C, the earphone 75 isattached by a connecting member 77 to the engagement member 79, whichcan itself be positioned along recessed groove 57 by sliding engagementmember 79 therealong and securing it with the thumbscrew 83. Accessory80 is an illuminator that can be similarly attached by sliding theengagement member 89 within recessed groove 57 and securing it withthumbscrew 83. FIG. 4b shows the mounting rail of FIG. 4a with the twoaccessories 75, 80 mounted in place.

FIG. 5 shows another mounting rail affixed to a helmet shell 51. In thisembodiment the mounting rail 55 on the left side of the helmet (shown)is extended forward by a front connecting element 94, which joins withthe mounting rail 55 on the right side of the helmet (not shown). Theentire mounting rail thus encircles three-quarters of the helmet shell51 and is secured by means of five fasteners 53, two on each side andone in the front, which desirably penetrate the shell using thethrough-holes shared with retention components (not shown). Thisembodiment may comprise additional attaching features, it beingunderstood that any particular version may have some, but notnecessarily all of the attaching features illustrated. In addition tothe recessed groove 57 already described, this embodiment has one ormore threaded holes 97, which serve as mounting points for an accessorythat can be threadably mounted therein. An attachment surface 99 on thefront connecting element 94 accepts accessories such as PVS-14 nightvision goggles to the front of the helmet. A hole 101 a on the left sideof the front connecting element 94 can be used in conjunction with asimilar hole 101 b on the right side to provide a hinged mounting pointin the front for an additional accessory (see FIG. 6). Finally, a slot103 allows a rear connecting element 107 to be attached as furtherdescribed in connection with FIG. 7.

FIG. 6 shows a face-protection accessory 105 hingeably affixed to themounting rail of the present invention using holes 101 a and 101 b. Theface-protection accessory 105 may be further supported by a bumper 107that braces against the helmet shell 51. Mounting holes 101 a, 100 bprovide a secure, hinged attachment to the helmet, allowing theface-protection accessory 105 to be hinged upward and out of the waywhen not needed.

With reference to FIGS. 5 and 7, a rear connecting element 107 isdesigned to mate with slot 103 a in mounting rail 55 on the left sideand to extend around the back of the helmet shell 51 to a similar slot103 b on the mounting rail on the right side of the helmet. The rearconnecting element 107 is desirably slightly compliant and conformalwith the outer shell 51 such that when a tension is established betweenthe two slots 103 a and 103 b, the rear connecting element 107 comesinto close contact with the shell 51. This rear connecting element 107,which creates a bridge under tension between left-side and right-sidemounting rails, allows the rails to better resist dislodgement byhorizontal or rotational forces. The tension may be established by apair of over-the-center latches 110 a, 110 b, which have ends adapted tofit into slots 103 a, 103 b, respectively, and to move hingeablydownward (as indicated by the arrows) so as to snap against connectingelement 107. Alternatively, tension can be provided by other suitablemeans known in the art such as tightening screws that pull two parts ofthe rear connecting element 107 together to contract its length.Accessories may be attached externally to the rear connecting element107 using any of the attaching features as described above in connectionwith FIG. 5. Alternatively, rear connecting element 107 can provide aprotected space for smaller accessories, such as electronic components,which can be stored within the space within the rear connecting element107 or between it and the outer shell 51.

Ear-Accessory Retention System

The general operation of an ear-accessory retention system in accordancewith the present invention is shown in FIGS. 8A-8C. FIG. 8A shows theleft side of a helmet shell 51, the right side having symmetricalfeatures and requirements. A hinge mechanism in accordance with thepresent invention, generally indicated at 120, is attached to a mountingrail 55, which is itself attached to the helmet shell 51 by means offastener 53. The hinge mechanism 120 supports an ear accessory(specifically, in the illustration, an earphone) 75, and allows theearphone 75 to extend below the terminal edge 122 of the helmet 51. Italso allows the earphone 75 to fit against the wearer's ear with thecavity formed by the protrusion or bulge 125 of the helmet 51.

FIG. 8B shows the hinge mechanism 120 in an intermediate position, asmay be the case when the wearer is engaging or removing the earphone 75.Pulling the earphone 75 causes a pivot arm 130 to rotate as the earphoneslides downward away from the wearer's ear. With the pivot arm 130 fullyrotated to a downward position, the earphone 75 can pass out of thecavity and beneath the edge 122 of the helmet shell 51.

As shown in FIG. 8C, rotating the earphone around its attachment postfacilitates further clearance from the wearer's head. From thisposition, the wearer can move the hinge mechanism 120 to a stowageposition described below, along the trajectory shown in FIG. 8D, or cancompletely remove the hinge mechanism 120 by loosening thumbscrew 83 andsliding engagement member 79 out of the recessed groove 57 of mountingrail 55.

The various components of the hinge mechanism 120 are shown in FIG. 9.Pivot arm 130 includes a yoke 130 a and a split-ring cap 130 b. Asplit-ring screw 135 (see FIG. 11) holds the components 130 a, 130 btogether, and with the two components joined, the pivot arm 130rotatably engages a post 142 extending from the earphone 75. A shoulderscrew 148 secures the yoke 130 a to the connecting member 77 and isdimensioned so that when fully tightened against shoulder nut 153 (seeFIG. 12A), it does not pinch too tightly, leaving clearance for the yoke130 a to rotate relative to the connecting member 77. The body ofconnecting member 77 and the edges 155 thereof form a C-shaped channelinto which the shoulder member 160 is slidably received. A pair of tabs167 formed on shoulder member 160 slide into complementary slots 169through connecting member 77. The tabs 167 are flexibly joined toshoulder member 160 so that they can be deflected under manual pressure.To releasably engage the shoulder member 160 to the connecting member77, the tabs 167 deflect as they enter slots 169 and then snap intoplace. The slidable connection between the connecting member 77 andshoulder member 160 provides adjustment of the earphones 75 in heightand may be freely sliding, or maintained by a friction fit, orpreferably provided with multiple positions by forming smallindentations along the body of connecting member 77 near the slots 169with resilient indexing features (e.g., as described below in connectionwith FIG. 14) formed on the body of shoulder member 160 (not shown),such that they “click” from one indentation to the next. To adjust for acomfortable position of the earphones 75 over the wearer's ears, thewearer manually slides connecting member 77 up or down relative toshoulder member 160 to adapt to different head shapes and ear heights.Yoke 130 a is preferably curved (as indicated at 173) so that when theearphone 75 is positioned over the wearer's ear, the microphone 176 isnot blocked.

With reference to FIG. 10, the pivot arm 130 of the hinge mechanism isshown separated from other components. Yoke 130 a is shown mated withsplit-ring cap 130 b, forming a split-ring hole 179. This hole 179 mayhave an internal ring or ridged structure and is sized to receive thepost 142 of a standard earphone 75 (see FIG. 9). The yoke 130 a has anindentation 182 suitably cut into the split-ring area to provideclearance for an earphone electrical cable exiting the earphone 75 nearthe post 142 (as described below in connection with FIG. 13). An armhole 185 is located at the other end of yoke 130 a to receive shoulderscrew 148, which rotatably attaches the pivot arm 130 to the connectingmember 77 (as best seen in FIG. 9). The distance between the center ofsplit-ring hole 179 and the center of arm hole 185 is indicated bydimension A. Preferably, dimension A ranges from 0.5 inch and 2 inches(e.g., 1.25 inches) in order for the mechanism to be easily operated bythe helmet's wearer.

With reference to FIG. 11, a counter-sunk hole 188 has a through-holediameter sized so that the shaft of split-ring screw 135 passes through,and may also have a larger-diameter recess to allow the head ofsplit-ring screw 135 to rest below the surface of split-ring cap 130 bto avoid protrusions. A keyed feature 191 a and a complementary groovefeature 191 b are formed in pivot arm components 130 a, 130 b,respectively, to index the two components one to another. Whensplit-ring screw 135 is inserted into countersunk hole 188 and screwedinto the threaded hole 193, the components 130 a, 130 b are drawntogether with key feature 191 a received within the groove feature 191b. Removing the split-ring screw 135 and separating the pivot arm intotwo parts 130 a, 130 b allows these components to be placed around thepost 142 of standard earphones 75 (see FIG. 9), and secured byreinserting and tightening split ring screw 135.

FIG. 12A shows pivot arm 130 and a mirrored symmetrical version of thispart 130′ connected to a connecting member 77 with a shoulder screw 148and a shoulder nut 153. Shoulder nut 153 is desireably a “T-nut” with alow profile to avoid interference with the earphone 75 (not shown). Tofacilitate tightening the shoulder screw 148, connecting member 77 has ablocking feature 196 that keeps shoulder nut 153 from rotating. Shouldermember 160 is shown assembled together with connecting member 77, withthe body of shoulder member 160 retained in the channels formed by edges155. Shoulder member 160 is designed to rotate about an axis passingthrough a detent ring 202, which is formed with protruding features. Awave washer (not shown) is used to force the protruding features ofdetent ring 202 in contact with similar or complementary features sothat rotational movement of shoulder member 160 occurs in approximately15° increments.

Further illustrated in FIG. 12A (with alternate embodiments shown inFIGS. 12B and 12C) is a stop feature 210 that mechanically interfereswith connecting member 77 to stop rotation of the pivot arm 130 (or130′) relative to the connecting member 77. The degree of allowedrotation can be critical to the amount of pressure holding the earphones75 (see FIG. 8A) against the wearer's head. Without the stop feature210, the pivot arm 130, 130′ would be able to continue rotation towardconnecting member 77, thereby allowing the earphone 75 to fall away fromthe wearer's head. The stop feature 210 prevents rotation beyond thepoint illustrated in FIG. 12A.

The alternate embodiment shown in FIG. 12B allows for adjustment of therotational interference of pivot arm 130 relative to connecting member77. Adjustment of this rotation may be desirable to accommodate fortolerance of the fabricated parts, differences in helmet sizes, anddiffering fixation positions of the engagement member 79 onto the helmet51, or simply to accommodate personal preference. In FIG. 12B, shoulderscrews 148 are tightened into a cam nut 212 (instead of the shoulder nut153). Cam nut 212 may be rotated by the user and held in place whiletightening shoulder screw 148 to cause more or less interference withstop feature 210.

In the further alternative illustrated in FIG. 12C, the shoulder screw148 is secured with shoulder nut 153 as previously shown in FIG. 12A. Anadjusting screw 215 threads into threaded hole 193 of yoke 130 a (or 130a′). Turning adjusting screw 215 varies the amount of interferencebetween pivot arm 130 (or 130′) and connecting member 77, therebyadjusting the amount of rotation.

FIG. 13 shows the hinge mechanism of the present invention mounted on ahelmet 51 and rotated to the stowage position. Also visible in FIG. 13is earphone electrical cable 217, which exits from the back side of theearphone 75 where pivot arm 130′ clamps around earphone post 142. Thehinge mechanism 120 is secured to the helmet by engagement member 79,which is held in recessed groove 57 of mounting rail 55 and secured withthumbscrew 83. A compression screw 226 holds shoulder member 160 to theengagement member 79. The compression screw 226, together with a wavewasher and compression nut (not shown), places shoulder member 160 andits detent ring 202 (see FIG. 12A) in compression so that the shouldermember will retain its position (i.e., resist rotation once positionedby the wearer). To move the hinge mechanism from the position of FIG. 8Ato that shown in FIG. 13, the wearer (i) pulls downward on the earphone75, causing pivot arm 130 to rotate downward to the position shown inFIG. 8C; (ii) pulls further to cause the connecting member 77 to slidedownward relative to the shoulder member 160; (iii) rotates shouldermember 160 toward the back of the helmet until the earphones 75 areagainst the back of the helmet shell 51; and (iv) slides connectingmember 77 toward the front of the helmet so that the earphone 75 doesnot cross the mid-line of the helmet, thereby providing room for thecorresponding earphone on the other side of the helmet to have a similarstowage position on its side of the back.

FIG. 14 shows pivot arm 130 and connecting member 77 detached from thehelmet and positioned to be slidably joined to a headband 229,facilitating use of the supported earphones 75 without a helmet. Theheadband 229 has a pair of tabs 231 with the same dimensions andfunctions as tabs 167 on the shoulder member 160 (see FIG. 9). The tabs231 can be momentarily depressed to insert the headband 229 into thechannel of connecting member 77 such that the tabs 231 slide in theslots 169. Indexing feature 234 “clicks” against small indentationsformed along the body of connecting member 77 near the slots 169 toprovide multiple adjustment positions to accommodate the size of thewearer's head.

Having described certain embodiments of the invention, it will beapparent to those of ordinary skill in the art that other embodimentsincorporating the concepts disclosed herein may be used withoutdeparting from the spirit and scope of the invention. The describedembodiments are to be considered in all respects as only illustrativeand not restrictive.

The invention claimed is:
 1. A method comprising: providing a mountingrail including a plurality of holes; placing the mounting rail on anouter surface of a helmet; aligning the plurality of holes of themounting rail with existing through-holes for retention straps in thehelmet; and inserting fasteners into the plurality of holes and thethrough-holes to affix the mounting rail and the retention straps to thehelmet, wherein the mounting rail includes a retaining groove.
 2. Themethod of claim 1, wherein the retaining groove has a flat inner surfaceand a pair of angled side walls opposed to the inner surface.
 3. Themethod of claim 1, wherein the retaining groove has a dove-tail shape.4. The method of claim 1, wherein the retaining groove is recessed. 5.The method of claim 1 further comprising: mounting an ear accessory tothe mounting rail.
 6. The method of claim 5 further comprising:positioning an ear cup of the ear accessory past a terminal edge of thehelmet and into a head cavity of the helmet in a use position.
 7. Themethod of claim 5 further comprising: positioning an ear cup of the earaccessory proximate a back of the helmet in a stowage position.
 8. Themethod of claim 1 further comprising: mounting a face shield to themounting rail.
 9. The method of claim 1 further comprising: mounting anight vision accessory to the mounting rail.
 10. The method of claim 1further comprising: mounting an ear accessory to the mounting rail in aplurality of different locations on the mounting rail.
 11. The method ofclaim 1, wherein the mounting rail has a curved surface configured toface the outer surface of the helmet when the mounting rail is attachedto the outer surface of the helmet.
 12. The method of claim 11, whereinthe mounting rail has a flat recessed groove.
 13. The method of claim 1,wherein a bottom edge of the mounting rail is generally aligned with abottom edge of the helmet when the mounting rail is affixed to thehelmet.
 14. The method of claim 1, wherein the mounting rail comprises afirst mounting rail, the method further comprising: providing a secondmounting rail having a plurality of holes, the second mounting railbeing a mirror image of the first mounting rail; placing the secondmounting rail on the outer surface of the helmet; aligning the pluralityof holes of the second mounting rail with existing through-holes in thehelmet; and inserting fasteners into the plurality of holes of thesecond mounting rail and the through-holes to affix the second mountingrail and retention straps to the helmet.
 15. A device comprising: amounting rail configured to attach to an outer surface of a helmet, themounting rail including a plurality of holes configured to align withexisting through-holes in the helmet for facilitating common affixationof the mounting rail and retention straps to the helmet, the mountingrail extending horizontally and then at an oblique downward angle alonga bend in a bottom edge of the helmet when the mounting rail is attachedto the outer surface of the helmet, wherein the mounting rail includes aretaining groove.
 16. The device of claim 15, wherein the retaininggroove has a flat inner surface and a pair of angled side walls opposedto the inner surface.
 17. The device of claim 15, wherein the retaininggroove has a dove-tail shape.
 18. The device of claim 15, wherein theretaining groove is recessed.
 19. The device of claim 15 furthercomprising: an ear accessory configured to be mounted to the mountingrail.
 20. The device of claim 19, wherein an ear cup of the earaccessory, when the ear accessory is mounted to the mounting rail, isconfigured to be positioned past a terminal edge of the helmet and intoa head cavity of the helmet in a use position and positioned proximate aback of the helmet in a stowage position.
 21. The device of claim 19,wherein the ear accessory is configured to mount to the mounting rail ina plurality of different locations.
 22. The device of claim 15 furthercomprising: a face shield configured to be mounted to the mounting rail.23. The device of claim 15 further comprising: a night vision accessoryconfigured to be mounted to the mounting rail.
 24. The device of claim15, wherein the mounting rail has a curved surface configured to facethe outer surface of the helmet when the mounting rail is attached tothe outer surface of the helmet.
 25. The device of claim 15, wherein themounting rail has a flat recessed groove.
 26. The device of claim 15,wherein a bottom edge of the mounting rail is generally aligned with thebottom edge of the helmet when the mounting rail is attached to theouter surface of the helmet.
 27. A device comprising: a mounting railconfigured to attach to an outer surface of a helmet, the mounting railincluding a plurality of holes configured to align with existingthrough-holes in the helmet for facilitating common affixation of themounting rail and retention straps to the helmet, the mounting railincluding at least two mounting features, wherein the at least twomounting features include a retaining groove.
 28. The device of claim27, wherein the retaining groove has a flat inner surface and a pair ofangled side walls opposed to the inner surface.
 29. The device of claim27, wherein the retaining groove has a dove-tail shape.
 30. The deviceof claim 27, wherein the retaining groove is recessed.
 31. The device ofclaim 27 further comprising: an ear accessory configured to be mountedto the mounting rail.
 32. The device of claim 31, wherein an ear cup ofthe ear accessory, when the ear accessory is mounted to the mountingrail, is configured to be positioned past a terminal edge of the helmetand into a head cavity of the helmet in a use position and positionedproximate a back of the helmet in a stowage position.
 33. The device ofclaim 31, wherein the ear accessory is configured to mount to themounting rail in a plurality of different locations.
 34. The device ofclaim 27 further comprising: a face shield configured to be mounted tothe mounting rail.
 35. The device of claim 27 further comprising: anight vision accessory configured to be mounted to the mounting rail.36. The device of claim 27, wherein the mounting rail has a curvedsurface configured to face the outer surface of the helmet when themounting rail is attached to the outer surface of the helmet.
 37. Thedevice of claim 27, wherein the at least two mounting features includesa flat recessed groove.
 38. The device of claim 27, wherein a bottomedge of the mounting rail is generally aligned with a bottom edge of thehelmet when the mounting rail is attached to the outer surface of thehelmet.
 39. The device of claim 27, wherein the at least two mountingfeatures includes one or more threaded apertures.
 40. The device ofclaim 27, wherein the at least two mounting features includes a slot.41. A method comprising: providing a first mounting rail including aplurality of holes; placing the first mounting rail on an outer surfaceof a helmet; aligning the plurality of holes of the first mounting railwith existing through-holes for retention straps in the helmet;inserting fasteners into the plurality of holes of the first mountingrail and the through-holes to affix the first mounting rail and theretention straps to the helmet; providing a second mounting rail havinga plurality of holes, the second mounting rail being a mirror image ofthe first mounting rail; placing the second mounting rail on the outersurface of the helmet; aligning the plurality of holes of the secondmounting rail with existing through-holes in the helmet; and insertingfasteners into the plurality of holes of the second mounting rail andthe through-holes to affix the second mounting rail and retention strapsto the helmet.